The present invention relates to a method for integrating at least one electronic component into a printed circuit board or a printed circuit board intermediate product, and to a printed circuit board or a printed circuit board intermediate product.
In the context of growing product functionalities of devices equipped with electronic components and increasing miniaturization of such electronic components as well as a rising number of electronic components to be mounted on printed circuit boards, increasingly more powerful field- or array-like components or packages having several electronic components are being employed, which have a plurality of contacts or connections, with ever smaller spacing between these contacts. The fixation or connection of such components increasingly requires the use of highly routed printed circuit boards, wherein it is conceivable that simultaneous reduction of the product size and of the components and printed circuit boards to be used, both with regard to the thickness and the area of such elements, will entail that mounting or arranging such electronic components by way of the required plurality of contact points on the printed circuit boards will become problematic or reach the boundaries of the possible resolution of such contact points.
So as to solve such problems, it has been proposed to integrate at least some electronic components in a printed circuit board, with reference being made in this regard to WO 03/065778, WO 03/065779 or WO 2004/077902, for example. However, the drawback of these known methods or embodiments of electronic components or parts integrated into a printed circuit board is that respective recesses or holes must be provided in a base element of a printed circuit board to receive such electronic components or parts, wherein additionally conductor tracks are formed before a component is arranged in such a hole. Soldering processes and bonding techniques are employed for making contact with the components, wherein contact points usually result between materials of different types between elements of the conductor tracks and the contact or connection points of the electronic components. Especially when such systems are used in environments that are subject to large temperature differences or ranges of temperature change, the use of different materials in the region of the contact or connection points, on the basis of different thermal coefficients of expansion, results in mechanically and/or thermally induced stresses, which can result in at least one contact or connection point to crack, and consequently lead to failure of the component. Moreover, it is conceivable that boreholes, in particular laser boreholes, which are additionally required for producing contact surfaces, cause further strain to the components. It is also disadvantageous that it is more difficult for the components, which are embedded in the recesses or depressions to be produced, to make contact with conductor tracks and contact surfaces by way of soldering pastes or bonding wires, or that this cannot be reliably achieved, especially when used with fluctuating temperature loads. Moreover, it is a drawback that potentially necessary high pressures and temperatures during the printed circuit board production process cause strain to the embedded and connected components. In addition, heat dissipation of optionally higher loaded electronic components is problematic.
Methods for producing a printed circuit board and for embedding an electronic component in a printed circuit board are known from US 2008/0196930 A1 and US 2010/0214750 A1, respectively, wherein clearances are provided in a conducting layer in accordance with contacts of a component to be integrated or fixed, so that a high effort with regard to the configuration and positioning of such clearances in consideration of the small dimensions of such contacts is required.
Modified embodiments for embedding components in a printed circuit board are disclosed in US 2009/0230541 A1, US 2006/0291173 A1 or US 2010/0044845 A1, which are directed to a simplification of the electrical connection, for example.
Therefore, it is the object of the present invention to minimize or eliminate said problems during the integration of at least one electronic component into a printed circuit board, and in particular to provide a method of the type mentioned above and a printed circuit board or a printed circuit board intermediate product, in which, using simple method steps, simple and reliable mounting of such an electronic component in a printed circuit board, or in a printed circuit board intermediate product, can be achieved, while providing particularly simple registration and having a reduced thickness of the printed circuit board that is to be produced, or the printed circuit board intermediate product that is to be produced.